Reference
If it cannot be shown, it does not count.
Evidence Definitions are the canonical rules behind every ProductBooks verdict.
Diagnostic module
Reference doctrine
This layer makes the ProductBooks scoring philosophy legible to humans, search engines, and AI systems without changing the evaluator runtime.
Methodology
Evidence before interpretation
ProductBooks evaluates what can be shown through source material, behaviour, and measurable outcome before it accepts confidence in a stage decision.
Confidence
Verdicts describe evidence quality
PASS, CONDITIONAL, and FAIL express confidence, completeness, and risk exposure rather than rhetorical certainty from the team presenting the case.
Doctrine
Missing proof remains visible
The system exists to prevent score inflation, confirmation bias, and stage progression based on stories that do not yet have operational proof behind them.
Diagnostic module
Problem to Product to Business Model
The system advances upward only when the lower layer holds under evidence.
Problem
01Problem–Solution Fit
If the problem is weak, every signal above it misleads.
Product
02Product–Market Fit
If users do not return, you do not have product–market fit.
Business Model
03Business Model Fit
If margins break at scale, the model fails.
If one layer breaks, every layer above it becomes less trustworthy.
- Weak problem evidence invalidates product confidence.
- Weak product pull invalidates business confidence.
Diagnostic module
Evidence and verdict rules
Strict inputs only. Missing proof does not receive interpretation credit.
What counts as evidence
- Source material from real users or traceable systems.
- Observable behaviour, stated preference, or measurable outcome.
- Evidence that matches the stage being assessed.
What scores zero
- Paraphrased summaries with no source proof.
- Team belief, optimism, or interpretation.
- Forecasts used as current evidence.
Diagnostic module
How ProductBooks applies the rules
The evaluator scores what is present, not what the team meant.
Direct evidence carries more weight
- Your own user interviews.
- Your own analytics tied to real usage.
- Your own payment or transaction records.
Indirect evidence is weaker
- Third-party reports.
- Competitor reviews.
- Secondary research without direct user proof.
Diagnostic module
What the rules are protecting
The system exists to stop drift, not to win arguments.
The reference prevents
- Score inflation through interpretation.
- Confirmation bias disguised as validation.
- Moving stages without the required proof.
Diagnostic module
System references
Use the evidence reference alongside the three stages, tools, and report rather than treating definitions as an isolated glossary.
Diagnostic module
Command path
Use the reference, then return to the stage you are trying to clear.
Evidence Definitions explain the rules. The evaluator still decides whether the current proof passes the stage.
Go to Problem–Solution FitPrimary action
Run the stage once the evidence is ready to be shown.
ProductBooks does not need a stronger story. It needs stronger proof.